The neural underpinnings of processing concrete and abstract semantics remain poorly understood. Previous fMRI studies have shown that multimodal and amodal neural networks respond differentially to different semantic types; importantly, abstract semantics activates more left-lateralized networks, as opposed to more bilateral activity for concrete words. Due to the lack of temporal resolution, these fMRI results do not allow to easily separate language- and task-specific brain responses and to disentangle early processing stages from later post-comprehension phenomena. To tackle this, we used magnetoencephalography (MEG), a time-resolved neuroimaging technique, in combination with a task-free oddball mismatch negativity (MMN) paradigm, an established approach to tracking early automatic activation of word-specific memory traces in the brain. We recorded the magnetic MMN responses in 30 healthy adults to auditorily presented abstract and concrete action verbs to assess lateralization of word-specific lexico-semantic processing in a set of neocortical areas. We found that MMN responses to these stimuli showed different lateralization patterns of activity in the upper limb motor area (BA4) and parts of Broca's area (BA45/BA47) within ∼100–350 ms after the word disambiguation point. Importantly, the greater leftward response lateralization for abstract semantics was due to the lesser involvement of the right-hemispheric homologues, not increased left-hemispheric activity. These findings suggest differential region-specific involvement of bilateral sensorimotor systems already in the early automatic stages of processing abstract and concrete action semantics.

处理具体和抽象语义的神经基础仍然知之甚少。之前的功能磁共振成像研究表明，多模态和非模态神经网络对不同语义类型的反应有所不同。重要的是，抽象语义会激活更多的左侧网络，而不是具体单词的更多双边活动。由于缺乏时间分辨率，这些功能磁共振成像结果无法轻松区分特定于语言和任务的大脑反应，也无法将早期处理阶段与后期理解后现象分开。为了解决这个问题，我们使用脑磁图（MEG）（一种时间分辨神经成像技术）与无任务的奇怪失配负性（MMN）范例相结合，MMN是一种跟踪大脑中单词特定记忆痕迹的早期自动激活的既定方法。我们记录了 30 名健康成年人对听觉呈现的抽象和具体动作动词的磁性 MMN 反应，以评估一组新皮质区域中单词特定词汇语义处理的偏侧化。我们发现，MMN 对这些刺激的反应在单词消歧点后约 100–350 毫秒内，在上肢运动区 (BA4) 和部分布罗卡区(BA45/BA47) 中表现出不同的侧化活动模式。重要的是，抽象语义的更大的向左反应偏侧化是由于右半球同源物的参与较少，而不是左半球活动的增加。这些发现表明双边感觉运动系统的不同区域特定参与已经处于处理抽象和具体动作语义的早期自动阶段。